Along with application and development of on-board display products, the on-board display product, which only has the display function previously, has become a control center of a vehicle. A size of the display screen of the on-board display product is increased gradually, and a physical button is gradually replaced by a touch button. People are expecting for better display quality and operation experience. As a result, a more advanced thin film transistor liquid crystal display (TFT-LCD) panel is required. In contrast to a mobile terminal having a 6-inch or smaller display screen, a panel of a large-sized display product has a large area, and a larger amount of liquid crystals is needed accordingly, so that the liquid crystals are prone to aggregate at a partial region of the display panel.
The on-board display product is typically fixed vertically in a vehicle, and thus when the vehicle is moving, the liquid crystals in the on-board display product are more prone to aggregate at the partial region due to factors such as gravity, acceleration, and high-temperature. In addition, cell gaps, amounts of liquid crystals and the like may be different in respective regions of the display panel, transmissivity in the respective regions may be different from each other, especially when the display product is in a black-white display mode). As a result, the display quality of the display panel may be adversely affected due to dark not uniform.